I am one of many baffled server administrators. We cannot figure out why out of the blue, microsoft decides to block incoming normal email into their servers,In my case, when I send an email to any popular free email account run by microsoft, I get the same S3150 error that the emails from my server IP are blocked.I have used their tools to try to delist, reached out to their support team, and they told me "I do not see anything offhand that would be preventing your mail from reaching our customers for the following IP (server IP address)".There is a serious bug somewhere within microsoft. And they had a long standing history of bugs and patch-fixes with their windows operating system probably since version 2.0 released before the 90's.If microsoft does not smarten up, then countless number of businesses could suffer and one or more lawsuits could be coming against them.
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